This relates generally to integrated circuits, and more particularly, to integrated circuits with metal-insulator-metal capacitors.
Metal-insulator-metal capacitors are typically formed within a dielectric layer that is interposed between two metal interconnect layers. The metal-insulator-metal capacitors are formed having a bottom capacitor electrode and a top capacitor electrode within the dielectric layer. The bottom capacitor electrode is separated from an adjacent metal interconnect layer by a layer of material such as silicon nitride. The metal-insulator-metal capacitor includes contact terminals that are coupled to the bottom and top capacitor electrodes. The contact terminals are formed in a metal interconnect layer that is adjacent to the dielectric layer (e.g., adjacent to the top capacitor electrode). The metal-insulator-metal capacitor is coupled to other circuitry on the integrated circuit by forming routing paths in the adjacent metal layer between other circuitry and the contact terminals.
Metal-insulator-metal capacitors are sometimes used as decoupling capacitors. Decoupling capacitors are often used to help provide more stable power supply voltages to circuitry on an integrated circuit. Decoupling capacitors shunt high frequency noise on direct current (DC) power supply lines to ground power supply lines, thereby preventing the noise from reaching circuit components on the integrated circuit. In a scenario in which a power supply is required to switch between different modes of operation, a decoupling capacitor having a sufficient capacitance can act as an energy reserve that lessens the magnitude of undesired dips in power supply voltage during mode switching events. Decoupling capacitors formed from metal-insulator-metal capacitors may occupy a disproportionate amount of area on the integrated circuit, because regions of metal layers that are used to form the metal-insulator-metal capacitors may be reserved to form contact terminals for the metal-insulator-metal capacitors.